Magnetically operated sealed switch unit



March 1, 1966 sc 3,238,325

MAGNETICALLY OPERATED SEALED SWITCH UNIT Filed Aug. 16, 1963 2 Sheets-Sheet 1 Inventor M. 5 CA TA Attorney March 1, 1966 MAGNETICALLY OPERATED SEALED SWITCH UNIT Filed Aug. 16, 1963 2 Sheets-Sheet 2 Inventor M. 5 CATA y M Worm M. SCATA 3,238,325

United States Patent 3,238,325 MAGNETICALLY OPERATED SEALED SWITCH UNIT Mario Scata, Monza, Milan, Italy, assignor to International Standard Electric Corporation, New York, N.Y., a corporation of Delaware Fiied Aug. 16, 1963, Ser. No. 302,583 Claims priority, application Italy, Aug. 30, 1962, 26,753, Patent 678,577 2 Claims. (Ci. sew-s7) This invention relates to switching contact devices and may be considered in the nature of an improvement on the sealed switches already revealed in the Italian Patent No. 623,442;

Such sealed switches have a number of important advantages: the contacts are protected from the effect of the atmosphere thus reducing substantially the corrosion of their parts, assuring long life and reliable operation, the switches are small in size, they are provided with pins to be plugged-in sockets, the contact elements can be placed inside a gas-tight metal envelope, other than glass, the sealing of which can be obtained by cold welding or by other processes. An inert gas is filled inside the envelope and pressurized to minimize arcing. A coil surrounding the vessel or a permanent magnet suitably placed ne-ar the latter is provided to create a magnetic field source for the actuation of the contacts.

The present invention is directed towards a more effi-cient and strong electrode construction to switch medium current (eg. two amperes) and to give the possibility of a preadjustment of the mechanical parts, outside the envelope.

This switch unit is manufactured for industrial applications and can be used in circuits carrying DC). or A.C. currents. In a preferred embodiment of this invention the contact members of the switch are rectangular in cross section. The electrodes are self-supporting from a base which carries the pins or terminals to be connected to the external electric circuit by soldering or through a socket.

' The various aspects and features of this invention will be pointed out and cleared by the following description considered in conjunction with the accompanying drawings in which:

'FIG. 1 is a longitudinal and sectional view of a relay switch embodying the invention.

FIG. 2 illustrates an exploded and enlarged perspective view of the double-throw contact elements to show the movable balancing magnetic member actuated by a magnetic field.

FIG. 3 shows a longitudinal and sectional view of an alternative embodiment of a sealed switch unit incorporating characteristics of the type illustrated in FIG. 1.

FIG. 4 shows an enlarged longitudinal and sectional view of another two way switching unit as an alternative embodiment of FIGS. 1 and 2 with a different mounting arrangement of the magnetic members,

FIG. 5 shows a side view of the switching unit of FIG. 4.

As shown in FIG. 1, the sealed switch unit comprises essentially an envelope 1, which could be a glass tube or a non magnetic metal tube. Inside this envelope carried by a base 2, are the magnetic and non-magnetic members 3, 4, 5, 6 together with the button contact elements 7, 8, 9 which are connected to proper pin terminals 10, 11, 12 protruding and insulated from the tube base 2 for connection to the external circuit.

As shown best in FIG. 2 the metal members are illustrated in detail. The terminal 12, rigidly secured to and insulated from the base 2, carries, at one end, a flat magnetic member 13 which extends parallel to the inice ternal wall of tube 1 (FIG. 1). Piece 13 is juxtaposed and welded, at the other end, to a non-magnetic fiat member 5, which is provided with two tabs 18-18 whose purpose will be explained later. The free end of member 5 supports a bracket member 4 of magnetic material provided with a tooth 17 which runs parallel to the fiat part 16 supported by member 5, the scope of tooth 17 will be explained also later, during the mounting stage. A non-magnetic resilient metal strip 6 is provided with a contact button 8 at one end thereof and is bent at an angle of at the other end which is engaged inside the bracket 4 and welded thereto.

A moving member 3 is formed of magnetic material and has a fiat portion 15 and a narrow portion 14. Two cuts 21, 21' are provided at its edges, near the center of member 3 to engage tabs 18- 18. Member 3 is bent upwards near the middle of its length and can freely oscillate around an axis passing through tabs 18-13. Resilient member 6 is also provided with a central portion 19 cut down to improve its elasticity and to serve for the scope which will be explained later.

The magnetic armature 3 of the relay is formed by a strip of magnetic material, a half portion 15 of which is of the same width as bracket 4 and the other half portion 14 of which is tapered to assume the shape of a finger. On the opposite edges of member 3, along the axis crossing the length of the strip are made two cuts 2121 to receive tabs 18--18. Member 3 is now bent upwards so that it can oscillate around the axis going through tabs 18-18, resting on fiat piece 13. The obtuse angle formed by member 3 will be adjusted as explained later.

In the mounting stage, resilient member 6 is first adjusted to come in contact, by its button 8, with stationary button 7 on terminal 11 supported by and insulated from base 2. Then the mechanical pressure between contact button 8-7 is increased pressing down tooth 17 on strip end 20. Magnetic armature 3 is then adjusted, its obtuse angle is varied or the tongue 19 is lifted until the correct gap is obtained between the overlapping facing ends '15 of the armature 3 and the flat portion 16 of bracket 4.

Thus when the switch is not subjected to a magnetic field, an electrical circuit is completed from the base terminal 11 through the contact buttons 7 and 8, the resilient strip 6, the magnetic bracket 4, the non-magnetic strip 5, the magnetic strip or plate 13 and the other base terminal 12.

The third button 9 is supported by terminal 10 and placed in front of the other side of movable contact button 8 leaving a suitable gap controlled by armature 3.

When all mechanical adjustments are made and checked, the protective cover 1 is sealed on base 2 and a pressurized inert gas is filled inside envelope 1.

For the actuation of the switch a magnetic field is provided, for example by means of a winding surrounding the envelope 1 or by a permanent magnet arranged in a suitable position along the envelope 1. When a magnetic field is present, the armature 3 rocks about points 1818 bringing its end face 15 towards bracket face 16 and thereby contact button 8 will leave stationary button 7 going towards contact button 9. When the electric contact is made, the pressure between buttons 8 and 9 will further increase because the air gap between armature end 15 and bracket face 16 was previously adjusted so that the opposite end 14 of said armature due to the resilience of strip 6 will further press the contact as the gap between end 15 and face 16 is closed by the action of magnetic force,

The unit above described may be used also with A.C. current by making a slight modification to bracket 4, the flat portion 16 of which is cut longitudinally for a certain amount to obtain two teeth one of which is surrounded with a copper ring.

An alternative arrangement to the previous design is shown in FIG. 3, Where is illustrated a sealed switching unit comprising'a-non magnetic envelope 1, generally of copper or aluminum, having leads brought into the envelope through suitable seals of insulating material (glass, ceramic) incorporated in the base 2.

The insidemagnetic structure with respect to that shown in FIG. 1 is modified in that the movable armature 3 of FIG. 1 is now made with a 90 bent piece of magnetic material forming a bracket with an arm 23 shorter than arm 24. This piece, which constitutes the movable armature of the relay is supported on the top of a nonmagnetic material metal strip 24 at a point 26 which acts as a fulcrum.

On apredetermined point 26' of the longer arm of said movable armature is welded an end of a resilient strip 27 of non magnetic metal, the other end of said resilient strip carrying a movable contact 28.

At the end 29 of the shorter arm of the movable armature hangs an end of a cylindrical spring 30 the other end of-which is secured to a fixed point 31. This spring, in the adjusting stage, is tensioned to adjust the pressure of the movable contact on the stationary contact 32.

A'metal strip of magnetic material 33 is bent in an S shape and welded at the end 34-of the wire terminal 35 sealed to the base 2 while the other end 36 of piece 33 is positioned in such a way that its face will be in front of the bottom end of the adjacent face 37 of longer arm 24 ofthe swingable armature. The air gap between contacts 28 38 is adjusted so that contacts 28-38 are closed before the ends 36-37 of the magnetic pieces are joined together under the action of an external magnetic field.

Thus, when the switch unit is energized, the bottom face 37 of the movable armature 2324 and top end 36 of the fixed piece 33 will be attracted therebetwe'en, the circuit between contact 32 and terminal 35 will open and a new circuit will be formed which includes the lead-in wire 35 the electrode 33, the resilient strip 24, a strap 39 (to improve the fulcrum contact) the movablearmature 23-24 the resilient strip 27, make contact 23 and stationary contact 38 with its lead-out wire through the base 2.

Referring to FIG. 4 there is shown a magnetic struc ture similar to that of FIG. 1, in which the movable armature is carried rigidly by the switching arm on which is welded the movable contact.

In this figure the same reference numbers as those employed in FIG. 1 were used to indicate same parts of the structure for sake of easy understanding.

The magnetic structure in FIG. 4 is carried by conductor 12 made with a short rigid metal wire which is sealed through the base 2 by means of glass or ceramic beads as 46. A portion of wire 12 is flattened inside the cover 1 to receive, by welding, a first fiat piece 13 of magnetic material on which is welded the end of a nonmagnetic member 5 to the other end of which is welded a magnetic member-4 like thatof FIG. 1.

A separation 40 is left between the two frontal edges of plane magnetic pieces 134, which rest on strip 5, the purpose of which will be explained later.

The magnetic bracket 4 has incorporated a tooth 44 and carries on its top side the upper end of the switching member 6 welded at point 45 thereon, the lower end carrying the movable double side button 8.

Two other rigid wires, 1041, inside the cover, carry at one of their ends the stationary contacts 79, in line with contact 8 andwires 10-11 protrude at their other ends from base 2 in the manner of wire 12. The faces of magnetic pieces 134, in front of and parallel to member 6 lie on the same plane.

A small tongue 42 protracts, at a suitable point, from 4. the switching member 6; a short rod being welded to tongue 42 at an angle of with respect to the longitudinal axis of member 6. The rod carries a magnetic plate 43 (FIG. 5) facing between the adjacent edges of the magnetic pieces 134.

The tooth 44, drawn out from bracket 4, provides a means to increase the pressure, when the relay is not energized, between movable contact 8 and stationary contact 7; this adjustment being made before sealing.

The air gap between the faces of the magnetic member 43 and magnetic pieces 13-4 is also adjusted before welding rod 41 to switching arm 6, so that, when the relay is energized, movable contact 8 can meet the stationary contact 9 an instant before the piece 43 comes in contact with pieces 13-4.

When the switch is energized by an-external magnetic field, the movable armature 43 is displaced to meet with the two internal adjacent faces of pieces 134, breaking, by means of arm 6, contacts 7-8 and establishing a new contact between button 8 and stationary contact 9 to close the electrical circuit abutting to terminals 10-12. The pressure between 8-9 will now increase until movable armature 43, fully will rest on adjacent plane pieces 13-4.

It is clear that the shape and the size of the various members, constituting these contact devices, can be different from the types embodied and described above. The magnetic material employed should have the best characteristics of permeability and the non-magnetic metals employed should have good electrical conductivity both for heat and electricity.

When'v'essel 1 is made of glass the metal structure can be self-supported before sealed into the' glass vessel, using the technique developed in connection with the manufacture of the other types of relays, described in our Italian Patents No. 570,614 and 573,752, in which is shown that the three terminals 10, 11, 12 can be joined together with a cross-bar, making all the adjustments in the metallic structure outside the vessel and sealing after it is inside the envelope, the external cross-bar being cut-away in the last stage of the manufacture to make free the three terminals.

Among the many uses to which this relay can be applied there is that of control of machinery in mines or in other ambients with explosive gases. I

When a group of three units as illustrated in FIG. 1 are suitably arranged, a three phase start-stop switch can be made and operated by the magnetic field of asingle permanent magnet which moves, as a plunger, along and inside of the group of the three units.

While the principles of the invention have been described above in connection with a specific embodiment and particular modification thereof it is tobe clearly understood that this description is made only by way of example and not'as a limitation on the scope of the invention.

What is claimed is:

1. A relay operable in response to a magnetic field comprising a cylindrical envelope formed of non-magnetic material,

means sealing one end of said envelope and a base sealing the other end, first, second and third wire terminals extending through and supported by said base to project inside and outside the envelope and insulated therefrom,

first and second stationary contact buttons rigidly supported inside the envelope on the first and second wire terminals which form an adjacent pair of terminals,

said third wire terminal supporting inside the vessel a plurality of members mechanically connected in sequence including a first magnetic member, a nonmagnetic member and a bracket of magnetic material,

said bracket having a first point fastened to the nonmagnetic member and being bent to provide support at a second point for members aligned in a different direction,

a movable resilient strip having a first end fastened to said second point of said bracket of magnetic material and having a second end carrying a switching contact button,

said resilient strip being mechanically biased so that its switching contact button is normally engaged with one of the stationary contact buttons and spaced from the other stationary contact button,

a movable armature positioned to be partially located within the space between the first magnetic member and said resilient strip,

said armature being positioned so that it can engage said resilient strip and responsive to changing magnetic fields to rotate about an axis and to deflect the resilient strip and to move the switching contact button from contact with one stationary contact to contact With the other stationary contact.

2. A relay substantially as claimed in claim 1, in which the armature comprises a bent rocking armature rotatable about a predetermined axis in response to changes in the magnetic field,

said non-magnetic member includes a pair of tabs,

said bent rocking armature includes two cuts,

said pair of tabs engages said two cuts to enable said bent rocking armature to rotate about an axis through said two cuts, and

said bent rocking armature includes a protruding end for controlling the switching contact button in response to said changes in magnetic field and for causing it to disengage one stationary contact button and to engage another stationary contact button.

References Cited by the Examiner UNITED STATES PATENTS 2,037,535 4/1936 Rankin 20087 2,242,636 5/1941 Wilson 20087 2,257,900 10/1941 Crum 20087 2,892,052 6/1959 Ducati 20087 2,957,961 10/1960 Juptner 20087 2,993,104 7/1961 Zimmer 20087 3,001,046 9/1961 Racz et al. ZOO-87 3,146,327 8/1964 Ohki et al. ZOO-87 FOREIGN PATENTS 894,378 4/ 1962 Great Britain.

BERNARD A. GILHEANY, Primary Examiner.

B. DOBECK, Assistant Examiner. 

1. A RELAY OPERABLE IN RESPONSE TO A MAGNETIC FIELD COMPRISING A CYLINDRICAL ENVELOPE FORMED OF NON-MAGNETIC MATERIAL, MEANS SEALING ONE END OF SAID ENVELOPE AND A BASE SEALING THE OTHER END, FIRST, SECOND AND THIRD WIRE TERMINALS EXTENDING THROUGH AND SUPPORTED BY SAID BASE TO PROJECT INSIDE AND OUTSIDE THE ENVELOPE AND INSULATED THEREFROM, FIRST AND SECOND STATIONARY CONTACT BUTTONS RIGIDLY SUPPORTED INSIDE THE ENVELOPE ON THE FIRST AND SECOND WIRE TERMINALS WHICH FORM AN ADJACENT PAIR OF TERMINALS, SAID THIRD WIRE TERMINAL SUPPORTING INSIDE THE VESSEL A PLURALITY OF MEMBERS MECHANICALLY CONNECTED IN SEQUENCE INCLUDING A FIRST MAGNETIC MEMBER, A NONMAGNETIC MEMBER AND A BRACKET OF MAGNETIC MATERIAL, SAID BRACKET HAVING A FIRST POINT FASTENED TO THE NONMAGNETIC MEMBER AND BEING BENT TO PROVIDE SUPPORT AT A SECOND POINT FOR MEMBERS ALIGNED IN A DIFFERENT DIRECTION, A MOVABLE RESILIENT STRIP HAVING A FIRST END FASTENED TO SAID SECOND POINT OF SAID BRACKET OF MAGNETIC MATERIAL AND HAVING A SECOND END CARRYING A SWITCHING CONTACT BUTTON, SAID RESILIENT STRIP BEING MECHANICALLY BIASED SO THAT ITS SWITCHING CONTACT BUTTON IS NORMALLY ENGAGED WITH ONE OF THE STATIONARY CONTACT BUTTONS AND SPACED FROM THE OTHER STATIONARY CONTACT BUTTON, A MOVABLE ARMATURE POSITIONED TO BE PARTIALLY LOCATED WITHIN THE SPACE BETWEEN THE FIRST MAGNETIC MEMBER AND SAID RESILIENT STRIP, SAID ARMATURE BEING POSITIONED SO THAT IT CAN ENGAGE SAID RESILIENT STRIP AND RESPONSIVE TO CHANGING MAGNETIC FIELDS TO ROTATE ABOUT AN AXIS AND TO DEFLECT THE RESILIENT STRIP AND TO MOVE THE SWITCHING CONTACT BUTTON FROM CONTACT WITH ONE STATIONARY CONTACT TO CONTACT WITH THE OTHER STATIONARY CONTACT. 